klemperer



May 5, 1942. w. B. KLEMPERER GUN INS TALLAT ION Filed Oct. 23, 1939 6 Sheets-Sheet 1 2. n 2 Po E Q N m M V r U WOZFGA/YG 6. Him

E x mw y 1942' w. B. KLEMPERER 2,281,772

- GUN INSTALLATION Filed Oct. 23, 1939 6 Sheetg-Sheet 2 a \9'\- N m w KLEMPERER May 5, 1942.

GUN INSTALLATION 6 Sheets-Sheet Z5 Filed Oct. 23, 1959 WOLFGfl/YG B. MEMPEEEB,

INVENTOR; fig

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May 5, 1942. w. B. KLEMPERER 2,231,772v

' GUN INSTALLATION Fild 0012. 23, 1959 6 Sheets-Sheet 4 WOLFGANG 5. KZEMPEEEE,

. INVENTOR;

' ATTORNEY.

y 1942- w. B. KLEMPERER 2,281,772

GUN INSTALLATION Filed Oct. 25/ 1939' e Sheets-Sheet e 74 I 'n o I '77 O O I. Z E 78. 73 79095 o 5 f 7/ 74 5 96 e9 m 11 u 5 9 78a 80 I ATTORNEY.

Patented May 5, 1942 uu rrec stares PATENT GFFiCE GUN INSCIPIHILATION Woflgang B. Klemperer, Los Angeles, Calif., as signor to Douglas Aircraft Company, Inc., Santa Monica, Calif., a corporation of Delaware Application October 23, 1939, Serial No. 300,789

20 Claims.

My invention relates to gun installations wherein a movable gun and a gun sight are mounted in association, and relates in particular to means whereby a, gun may be mounted and operated in a restricted area.

It is an object of the invention to provide a gun mount enabling the mounting of a gun and the gunsight therefor in a position where but little room is available for occupancy of a gunner. The invention is of especial utility with, but not limited to, the tail, wings, and nacelles of aircraft where these parts provide only restricted room or space for the mountin of the gun and gun sight and for the gunner who is to aim and operate the gun.

It is a further object of the invention to provide armament for protection of those parts of an aircraft which now constitute the blind spots in the defense of the aircraft. Such a blind spot is the space to the rear of the tail of an airplane for the reason that the tail control structure of an aircraft lies between the gun turret-s on the fuselage and the space disposed to the rear of the tail. Diificulty has been encountered in the mounting of a gun in the tail of an airplane for the reason that even in craft of relatively large size the space in the tail is relatively restricted due to the convergence of the external wall of the tail structure. The present invention makes possible the use of a gun, under control of a gunner, in small structures, such as the tail of an airplane, providing just sufficient room to receive the gunner, but permitting him little or no movement.

In the ordinary use of a machine gun, the butt of the gun swings as the gun is aimed, and the gun sight is ordinarily mounted on a swingable gun support. The gunner must move his head and ordinarily at least the upper part of his body so as to keep his eye aligned with the 4 a gun in the tail of an airplane or in other housings of similar small size. The present invention makes it possible, under conditions such as set forth in the foregoing, to mount a gun so that it may have universal movement in an angular range of at least 20 in any direction from the longitudinal axis of the aircraft fuselage, to cover the blind spot at the tail of the airplane.

It is an object of the invention to provide an aircraft having a gun to shoot rearward from the tail thereof and a chamber spaced in close vide a gimnery means comprising a gun support-' ed for universal movement so that it may be aimed, and having sighting means for the gun,

the eye piece of which is so positioned that substantially no movement of the gunners head is required in use of the gun sight to aim the gun at a target situated within the angular range of the gun. The invention makes it possible to reduce the space required for the mounting of the gun and for occupancy by the gunner to substantially a minimum, for the reason that space need not be provided to allow movement of the gunners body as is ordinarily necessary to enable him to follow with his eye the eyepiece of a gun sight which moves with the gun.

It is a further object of the invention to provide a gunnery device wherein the gun is movably supported relative to the wall structure of an enclosure, and wherein at least the eyepiece of the gun sight remains in a fixed relation to the supporting structure in which the gun is pivotally mounted for swinging movement enabling it to be aimed at a target.

It is a further object of the invention to provide a gunnery device including a gun swingable for the purpose of aiming the same, a means for producing a visual image of the field in which the gun may be aimed, and also means moving in accordance with the movement of the gun to indicate in the image of the field the point at which the gun is aimed at any time.

A further object of the invention is to provide, in conjunction with the gun which is movable for the purpose of aiming, a gun sight having means for producing in a focal plane an image of the field in which the gun may be aimed, a reticule movable substantially in the focal plane and means for operatively connecting the gun with the reticule to move the same in accord ance with the movement of the gun. In the prefexred form of the device, the gun sight, which remains in a fixed position relative to the supporting structure, produces a visible'image of be directed at different points in the held. when the reticule coincides with the visual image of a target in the field, information is imparted to the gunner that the gun is pointed at the target. In a preferred practice of the invention, the

. reticule embraces a central point and concentric rings to which reference may be had by the gunner in correcting for trajectory, deflection, etc.

It is a further object of the invention to provide an aircraft tail structure having a telescope projecting therefrom in a fixed position and walls or doors which form a portion of the external wall structure of the aircraft tall, with means for moving such doors or walls into open position so as to provide a port through which the gun may project and in which it "may be moved for purpose of aiming, with means enabling the gunner to use the image obtained in the optical system of the telescope as a guide for aiming of the gun. In accordance with the preferred practice of the invention, the telescope is continuously sighted upon a prescribed area or field and any object which enters this area will be in view of the gunner, who, when he perceives a target in his range of vision may be guided in pointing the gun at the target by reference to the position and movement of the reticule in the image of thefield.

It is an object of the invention to provide a telescopic gun sight of the character described, having means for preventing fogging of its interior lens surfaces, such means comprising a means for dehydrating the air which enters the shell or housing which encloses the lens system.

Further objects and advantages of the invention will be brought out in the following part of the specification.

Referring to the drawings, which are for illustrative purposes only:

Fig. 1 is a side elevation showing a preferred embodiment of my present invention with a gun= ner in normal position for manipulation of a gun.

Fig. 2 is an enlarged fragmentary plan view taken substantially as indicated by the line 2-2 of Fig. 1.

Fig. 3 is an enlarged fragmentary cross-section taken substantially as indicated by the line 33 of Fig. 2.

Fig. 4 is an enlarged fragmentary partly sectioned view taken, substantially as indicated by the line 4-4 of Fig. 3 to show the swivel supporting means for the gun and the means for transmitting to the reticule mechanism of the gun sight movements corresponding to the move- 7 ments of the gun.

Fig. 5 is a plan view taken from the position indicated by the line 5-5 of Fig. 4.

Fig. 6 is a fragmentary sectional view taken as indicated by the line b@ of Fig. 4.

Fig. 7 is an enlarged fragmentary section taken as indicated by the line ll-l of Fig. 1.

Fig. 8 is a fragmentary,section' taken on a plane represented by the line 8-8 of Fig. '7. Fig. 9 is a diagram of the lens system of the gun sight.

Fig. 10 is a fragmentary cross-section through the desiccator of the gun sight.

In Figs. 1 to 3 I show somewhat diagrammatthe rib 28a.

aesmva ically the tail structure 21! of an aircraft. In

modern airplanes this tail structure is of somethe reason that the principles of application thereof are well known. The wall of the tail structure may include a plurality of metal ribs 2i to which a suitable covering element 22 is applied, such covering element preferably being sheet aluminum; which forms the external surface of the wall. At the extremity of the tail structure, portions 23 and 2 3 of the wall are hingcdly supported so as to provide doors which may be swung outward from closed relation, as shown by dotted lines 25, to open relation, as shown by full lines in Fig. 2. The front edges 26 of these door members 23 and 2d are secured by hinges 27 to the essentially vertical portions of the rib 2 la, It is upon these hinges 2? that the doors are swung between closed and open positions by an actuating means 28, which may be in the form of a simple toggle, as shown.

The door actuating means 28 consists of a longitudinal rod 29 supported by rollers 36 carried on a cross brace 3| which is secured to the rib 25a, and by means of a single roller 32 which projects down from the front end of the rod 29 so as to lie between a pair of parallel guide rods 33. the front ends of which are supported on a bracket 3% which projects rearward from the cross brace 3E, and the rear ends of which guide rods 33 are carried by a bracket 35 secured to a wall reinforcing member 36 disposed rearward of As shown in Figs. 1 and 2 small clevises 37! are securedto the inner faces of the door members 23 and 2t, and toggle bars or struts 38. hingedly connected to the members Lil, are

end of the longitudinal bar 29. The rod 29 has a handle M at its forward end by which it may be given longitudinal movementby the gunner ll shown in Fig. 1. When the rod 29 is shoved rearward from the position in which it is shown in Fig. 1', the hinge pins 39 at the rear end thereof will swing the toggle bars 38 into aligned position between the clevises 37, as shown in Fig. 2, so that the doors 23 and 2d will be held in open position. As the rod 29 is pulled forward from its position of Fig. 2 so that the hinge pins 39 are moved forward to their positions in Fig. 1, the inner ends of the toggle bars 38 will be swung forward toward the angular or retracted position in which they are shown in Fig. 1 and the toggle formed by these bars 38 will be thus collapsed, and as the bars 38 move into diagonal relationship the doors 23 and 28 will be moved into closed position.

Above the bracket 3d there is a bracket 62 which is secured to a face of a lateral cross brace d3, whichis likewise secured to the rib 2m in a position spaced above the cross brace 31!. As best shown in Fig. 4, the brackets 34 and d2 carry vertically aligned ball bearings M and lb, by Whicha gun yoke '36 is supported for rotation on the vertical axis A-- A, Fig. 4, after the manner of a gimbal ring.

This gun support comprises a pair of side members fill and id in laterally spaced vertical planes and connected at their lower and upper ends, respectively, by members 49 and 5d. Pivot pins ti and 52 project respectively from the members of a bracket 61.

49 and 58 into the bearings 44 and 45, thereby providing the means of engagement of the yoke 46 with the bearings in which the yoke is swung ponent of the universal movement results in a swinging of the gun on the axis BB of the yoke 46, and the horizontal component of this movement results in a rotation of the yoke 46 on the axis A-A. To hold the gun in a fixed position of non-use, a strut 5'! is provided, this strut being connected by hinges 58 to a rib 2 lb and having a hook 59 at its free end to engage a bar 60 which is connected to the inner end of the gun cradle 54. When the gun'is secured in a position of non-use, as shown in Fig. 1, the barrel 6| thereof will pro- ,iect through a suitable aperture 62 provided between the meeting edges of the doors 23 and 24. This aperture 62, as shown in Fig. 2, may be formed in the edge of one of the doors, for example, the door 23. For use of the gunner 4| to aim the gun 55,

telescopic gun sight 63 is mounted in a position above the gun and so that the field piece 65 thereof will be directed toward the area or field lying to the rear of the tail of the aircraft. The cone space of the angular field of the telescopic gun sight 63 covers slightly more than the field in which the gun may be aimed and fired, thereby making it possible to fire the gun at any point or target which may appear in the 'visual image brought by the gun sight 63 to the eye of the gunner. The gun sight 63 comprises a complement of optical lenses including an eyepiece lens system in the eyepiece 64,,and also an objective lens system, with suitable erecting lenses disposed therebetween. Preferably the lenses of the gun sight 63 are all enclosed by a suitable housing, comprising the tubular structure 56 which is rigidly secured to the aircraft structure by' means This housing for the lens system also includes a reticule box 68, which is-connected by means of an angle 69 to the tail structure of the aircraft. This reticule box 68 is disposed adjacent to the eyepiece of the gun sight 63. Within the reticule box 68 a reticule is movably mounted so that it may move in, or parallel to, the focal plane of the eyepiece. Means are provided, as hereinafter described, for moving the reticule so that it will appear in the visual image which passes to the eye of the gunner, in a position to indicate the point in the field at which the gun 55 may be aimed at any time.

As shown by Fig. 7, the reticule 10 is carried by a reticule frame H, which is supported in the box 68. One portion 12 of this frame I I, as shown in Fig. 8, projects into a horizontal frame 13 in a manner to slide horizontally or laterally between the upper and lower bars 14 thereof. The remaining portion 15 of the'reticule frame II projects into a vertically elongated frame 16 in a manner to be slidable along the bars ll of such frame 16. The horizontally elongated frame 13 is engaged by a vertical screw 18 so as to be moved vertically in either direction from the position in which it is shown in Fig. 'I. A horizontal screw 19 engages the vertically elongated frame 16 and may be operated to move the frame 16 horizontally in either direction from the centralized position there'of shown in Fig. '7. These screws 18 and 19 are supported so as to project within the box 68 by suitable anti-friction bearings 18a and 19a. It will be recognized that when the screw 18 is rotated, vertical movement of the frame 13 will move the reticule frame II in vertical direction, and such reticule frame 1| will slide along the vertical bars H. When the screw 19 is rotated, the vertically alongated frame 16 will move the reticule frame .11 along the horizontal bars 74 of the frame 13; accordingly, by operation of screw 18 or screw '19 the reticule 18 may be moved either vertically or horizontally, why a simultaneous rotation of the screws 18 and 19 the reticule") may be moved in any angular direction between vertical and horizontal.

The invention provides means for rotating the screws 18 and I9 in accordance with the vertical and horizontal components of the movement of the gun 55 so that the movement of the reticule I0 in the image of the field to which the gun sight 63 is directed will be in accordance with the movement of the gun and therefore the reticule will indicate in the visual image the point in the field to which the gun is pointed. In order to transmit rotation to the screw I8 in accordance with the vertical component of the movement of the gun 55, I provide a cable which runs over a spool 8| mounted on the exposed end of the screw 18 and is carried to a wheel or drum 82 rotatably supported on the exterior of the side member 48 of the yoke 46 by means of a shaft 83 which projects through the side member 48 and on the inner end thereof carries a gear '84 engage by a gear segment 85 which is adjustably connected to the gun cradle 54 so as to swing around the shaft 53 as the gun cradle 54 is swung vertically. The gear segment 85 includes a plate 86, the lower end of which is turnably mounted on the shaft 53 and has projecting lugs 81 to carry adjusting screws 88 which engage spaced portions of the cradle 54. It will be perceived that by suitable adjustment of the screws 88, the segment 85 may be swung relative to the cradle 54 on the shaft 53 and that when the cradle 54 is swung on the shaft 53 the movement thereof will be transmitted through the screws 88 to the segment. Rotational movement of the'segment 85 will transmit rotation through the gear 84 to the drum 82 and the cable 80 will be moved so as to rotate the spool 81 and thereby turn the screw 89, 98,91, and 92 are provided. The pulleys 89.

and 96 receive the portions of thecable 88 which extend upward from the drum 83 and are supported on the upper end of the shaft or pin 52 by means of a bracket 93, which accordingly rotates with the yoke 46 on the vertical axis A--A. The pulleys 9| and 92 are supported by means of a bracket 94 which is secured to the upper bearing bracket 42. These pulleys 9i and 92 are substantially longitudiually aligned with the spool 8| and engage those portions of the cable 80 extending from the pulleys 89 and 9D to the sheave 8|.

To rotate the screw 19 in accordance with the lateral or horizontal component of the movement of the gun 55, I provide a cable 95 which runs over'a spool 96 fixed on the exposed end of the screw 19, and extends to a wheel or drum 9! which, as shown in Fig. 4, is fixed on the upper end of a shaft 98 supported for rotation by bearings it carried by a bracket flit which is secured by bolts iti to the cross brace 33 in a position between the bracket t2 and the reticule box 68. One portion of the cable 95 is carried directly to the wheel 9i, but the other portion of the cable extends over a pulley m2 supported in the position thereof shown in Fig.5 by means of an arm H33 which projects from the bracket i838. n the lower end of the shaft 98 a gear its is secured in position to be engaged by a gear segment tilt which is connected to the yoke or frame it so as to rotate therewith on the vertical axis A-A. As best shown in Figs. 4 and 6, the gear segment me comprises an upper plate lull connected by a spacer bar hit with a plate Hi9 which has limited swinging movement on a screw Mt threaded coaxially into the lower end of the shaft element 532.

Adjusting screws 6 i2 are threaded through the extended ends of the bar ltd to engage the top member hit of the yoke 66. By a suitable in and out adjustment of the screws M2 the gear segment we may be swung for limited adjustment on the axis of the screw Mt.

As the gun 55 is swung for purpose of aiming the lateral component of its movement will be accompanied by a rotation of the yoke so on the axis A-A. This rotation will be transmitted through the segment are to the gear Hi5, thereby rotating the wheel @i so as to move the cable 95. Movement of the cable at will transmit rotation to the screw it through the spool 9@, thereby causing a corresponding lateral movement of the vertically elongated frame it which will move the reticule frame ii in the horizontal or lateral guides formed by the bar id of the frame iii. If the gun is swung in any diagonal direction, or in any direction other than vertical or horizontal, the vertical and horizontal components of the movement imparted to the gun will be transmitted through the gear and cable means to the reticule frame it with the result that the reticule it will be given a movement in the reticule box similar to the movement of the gun, and when the gun is brought to rest in any position, the position of the reticule it? in the image which passes through the'focal plane f--f will indicate the point in the field at which the gun is pointed. The reticule it may comprise merely 'a central point, or it may be the point of crossing of strands or lines H8. wise embrace concentric circles Mil for'reference of the gunner in compensating for the various elements for which the sighting of the gun may be corrected, for example, drop of trajectory, parallax, lead, etc.

It is recognized that in the construction of the device corrections for certain conditions must be made. A simple proportionality of the reticule displacement with the angular movement of the gun and its yoke would introduce a number of aiming errors which will now be discussed together with proposed means for combatting them.

Tangent correction may be accomplished in accordance with the following. If the eyepiece were optically equivalent to a peephole at a focal distance ,i fromthe reticule plane, then the lateral displacement of the crosshair in the reticule plane should be y tan a (01 being the'longitude angle of the transverse gun yoke rotation) if the aim is to remain parallel to the gun barrel. in order to produce the tangent function, a suitable kinematic linkage can be provided. For in stance, I propose to crown the cable drums ti and so on the lead screw shafts in torus fashion.

The reticule iii may likeaaemra As one side of a cable unwinds from a drum and The focal image of the field may be distorted: a

point at a radial distance r from the optical axis in the reticule plane appears at a sighting angle whose tangent is 1/) so long as a is small but it may difier more and more from r/f as a increases towards the edge of-the field. In order to correct for this influence ll propose to crown the cable drum some more (or less) than for the tangent correction according to whether the distortion is negative or positive. In tact, with positive distortion exceeding the tangent influence, the generatrix of the torus becomes concave rather than convex.

If the distortion inherent to the eyepiece is pronounced, then another error creeps in when the gun is moved obliquely in space, i. e., if excursions in longitude and latitude are made simultaneously. This error is due to the fact that a pair of orthogonally displaceable reticule positioning frames position the cross hair at the geometric resultant r= /a." -j-y of the horizontal and vertical component displacements a: and 1/. They will, however, appear to the eye at an angular excursion greater than c= /a +b if a or b are the apparent excursions of a: or y alone in the absence of one another, because the angle corresponding to r is greater than that to either It or 2/.

To minimize this diagonal distortion error which. is zero along the axes and a maximum at 45 between them; I find it convenient to split the difference and so figure the drum shape that a small negative error is deliberately incurred, but the extreme error is accordingly mitigated and the area over which the error is kept tolerably small is vastly extended.

1 am aware of the fact that a kinematic error is introduced by swinging the gun in a universal joint system of pivots through longitude and latitude angles, these two motions not being kinematically equivalent as the former is a rotation about an axis fixed in the airplane and the latter is not. Therefore if the aforementioned orthogonal distortion is equally corrected for both the horizontal and the vertical frame drives, then the gun is actually pointed neither at a pdint indicated by the coordinates x, y, nor by-a, b, but by some point vertically above the point a. This error is a function of both longitudinal (or) and latitudinal (c) excursion; it is zero at a=0 or 5:0 but maximum in a region where both angles are large and a slightly larger than ,3. To minimize this error I again find it convenient to deliberately introduce a small negative error, thereby reducing the extreme error and expanding the area of tolerably small error. I find it convenient to achieve this compromise by a slight change in the transmission ratios, the vertical drive being geared up more than the horizontal. It should be noted that the radial component of the latitude curvature error opposes the diagonal distortion error if the distortion is positive. L

'If the optical and kinematic corrections were such thatthe aim is parallel with the gun barrel and even if additional corrections for trajectory drop and range, and other inherent ballistic deviations were accurate, there would remain the phoronomic influences of the speed components across the line of sight both of the target and of the muzzle. To compensate these completely under all firing conditions of aerial combat elaborate apparatus would be necessary. However, the most dangerous conditions may be those for which the enemy would be considered in an advantageous position for attack, i. e., flying ap proximately toward the craft we wish to defend while the latter proceeds on its mission in steady flight without maneuvering to shake off the pursuer. In this condition the most important need for phoronomic correction is that due to the defenders own fiight speed being imparted to the projectile as it leaves the muzzle.

The proper correction for this error consists in an excess excursion of the reticule approximately in inverse proportion to the ratio of projectile velocity to the difference between projectile and flight velocity. I propose to so design the kinematic transmission that the ratio between reticule motion and gun motion is approximately increased by the stated amount over that required for optical correction only. By way of example this increase would be of the order of 15% for a flight speed of-400 ft./sec.'and a projectile speed of 3000 feet/sec.

Various means are provided to make adjustments on the reticule drive system. Slight corrections for bore sighting or .windage and elevation errors inherent to the gun can be made by adjusting the turnbuckles H which are inserted in the cables. effected by means of screws H2 and 88 positioning the segments on the yoke and gun carrier respectively. It is then unnecessary to provide adjustment on the telescope proper so that the latter can be permanently mounted in the airplane structure although shock absorbing elements may be inserted in this mount to keep vibrations away from the gunners eye.

Variants The means provided to achieve the recognized functions hereinbefore indicated may take a variety of forms. The reticule was described as being placed in the focal plane of the eyepiece while it can also be positioned in the focal plane of the field lens. The former position has the advantage that more room is available in the streamlined airplane structure to accommodate the reticule housing in a place where the width of the structure is greater. The cablespools BI and 96 have each been described as a single curved winch drum which winds up the one cable as it pays out the other. To avoid the (very slight) tightening or slackening of the rigging tension of the cable separate individually curved drums may be provided for each cable end ensuring that the cables wind up and pay out tangent to exactly the same radius. such as a spring loaded idler may be provided instead to keep the cable rigging load constant.

The cable drive may be replaced by other mechanical transmission means such as linkages or torque tubes or by electrical means such as Selsyn motors or servo motor controls. The-unproportionality corrections may then be introduced by means of cams, linkages, unround gears or the like. The lead screw spindles and nuts may be also replaced by cams and cam followers.

The reticule has been described as a frame II floating between two guiding frames 73 and I6: There are other kinematic means to position the reticule in two coordinates. For instance, one frame may travel upon and with respect to the other after the manner of a microscope stage. Also it is possible to build some curvature into one or both frames, thereby guiding the reticule on a curved surface instead of in a focal plane provided the optics have sufiicient depth of focus. This artifice of curved reticule travel can then be put to use in effecting some of the corrections previously described, notably that of the latitude curvature error.

As a further feature of the invention, the gun sight 63 is provided with a desiccator H6 which may be suitably connected to the housing of the gun sight, for example, as shown in Fig. 1. The wall II! of the housing 66 has a breather opening or passage IIB connecting the interior of the housing 66 with the exterior atmosphere through the desiccator I I6, the internal spaces of the gun sight 63 are all inter-connected so that there may be a relatively free flow of air from one internal space to another as pressure conditions between the spaces within the gun sight 63 vary. In Fig. 10 the desiccator IIB is shown as including a fitting H9 which is secured to the wall III so that a, recess I therein will communicate through. a passage I2I with the breather passage II8. vA wall I22 of the recess I20 is threaded so as 'to receive a detachable chamber in the transverse perforate wall I24 against which a Further adjustments can be 1 desiccator cartridge I25 may rest. Between the transverse wall 124 and the perforate end wall I21 of the tube I23'there is a valve means I28 to isolate the desiccant I29 of the cartridge I25 from moisture of the external atmosphere, but permitting such flow of air as may be required for the normal breathing of air in and out of the gun sight 63.

The valve means I28 includes a transverse wall I30 having an inlet opening I3I and an outlet opening I32, these openings being respectively provided with flow restraining valve closure elements I33 and I34, held respectively against the inner and outer ends of the openings I3I and I32 by small springs I35 and I36.

When the tube I23 is removed from the fitting II9, the desiccant cartridge I25 may be inserted through the open inner end I31 of the tube. Against the pervious wall I38 of the cartridge I25 a dust filter I39, comprising a wall of fibrous material may be placed, this being followed by a perforate wall I40 against which a spring I4I presses when the tube I23 is again attached to the fitting 9. Should there be a decrease in the pressure of the atmosphere external to the gun sight 63 and the desiccator I23, for-example, as the result of ascent of the aircraft, there will be a flow of air out through Other means the breather passage H8 and out through the outlet valve opening I32 when the pressure differential is suflicient to displace the closure member I34 against the relatively small pressure 'of the spring I36. Whenth'e external pressure to such extent that there will be no fog ing oi the lenses or optical surfaces within't-he gun sight at. The desiccator lid is situated in a po- "for the purpose of aiming the same; a gun sight mounted rigidly in'said supporting structure and having optical means to produce an image of the field in which said gun may be aimed; and means operating to indicate in said image the point in said field at which said gun is aimed, said indi-- cating means being connected to said gun so as to move relative to the gun sight in accordance with the angular movement of said gun as said gun is aimed at a target appearing in said field and in said image.

2. In a gunnery device of the character described, the combination of: a gunners support; an optical means disposed in a position contigucue to said gunners support and having a lens system for producing an image of the field at which said optical means is directed; a, gun swingably supported so as to be aimed at points in said field and in such manner that asit swings its angle relative to said optical means will change; and means connected to said gun so as to be controlled by the movement of said gun,

' to indicate on said image the pointin said field at which said gun is aimed atany time.

3. In a gunnery device of the character described, the combination of a gun sight having means defining a'plane intercepting the path of light carrying an image from-a field to a receiving optical element; a gun mounted for movement relative to said gun sight and so as to be aimed at points in said field; and means connected to said gun so as to be controlled in accordance with the movement'of said gun relative to said gun sight, to indicate in said plane a point positioned in accordance with the point in said field at which said gun is aimed.

4-.In a gunnery device of :the character described, the combination of: a gun sight having optical means to produce in a focal plane an image of the field at which said gun sight is directed; a gun supported movably relative to said gun sight and so as to be aimed at different points in said field; and means connected to said gun so as to be controlled by the movement thereof relative to said'gun sight, and operating to indicate in said focal plane and said image, the point in said field at which said gun is aimed.

5. In a gunnery device of. the character described, the combination of: a telescopic gun sight having optical means to produce an image of the field at which the gun sight is directed; a reticule movable in the field of view of said gun sight and in a plane transverse to the line of sight; a gun mounted for movement relative to said gun sight so as to be aimed at points in said field; and means connected to said gun so as to be controlled by the movement thereof, and operating to move said reticule in accordance with the movement of said gun relative to said gun sight so that said reticule will indicate in said image the" point in said field at which said gun is aimed.

6. In a gunnery device of the character ilescribed, the combination of agunners support;

assures a gun sight for use of a gunner occupying said support, said gun sight being supported stationary relative to said support and having optical means to produce in a focal plane an image of the field at which said gun sight is directed; a gun supported in swingable relation to said gunner's support and said sight so as to be aimed by said gunner at points in said field; and means connected to said gun so as to be controlled by the angular movement thereof, and operating to indicate in said focal plane and said image, the point in said field at which said gun is aimed.

7. In a gunnery device of the character described, the combination of: a gunners support; a telescopic gun sight supported in a substantially stationary relation to said guinners support so as to be used by a gunner occupying said gunners support, said gun sight having optical means to produce an image of the field at which the gun sight is directed; a reticule movable in the field of view of said gun sight and in a plane transverse to the line of sight; a gun supported inmovable relation to said gun sight and so as to be aimed by said gunner at points in said field; and means connected to said gun so as to be controlled by the movement thereof, and operating to move said reticule in accordance with the movement of said gun so that said reticule will indicate in said image the point in said field at which said gun is aimed.

8. In a gunnery device of the character described, the combination of: a telescopic gun sight having means to produce an image of the field at which'said gun sight is directed; reticule means movably mounted in the field of view of said sight; means for moving said reticule means in a first direction and means for moving said reticule means in a second direction crossing said first direction, both directions being transverse to the line of sight, whereby said reticule means may be moved to any position in said field of View; a gun supported for universal movement relative to said gun sight, so as to be aimed at points in said field; means connecting said gun and said reticule means so that angular movement of said gun in one plane will move said reticule means in said first direction thereof; and means connecting said gun and said reticule means so that movement of said gun in a plane transverse said first mentioned plane will move said reticule means in said second direction thereof.

9. In a gunnery device of the character described, the combination of: a fixedly mounted telescopic gun sight having means to produce in a plane an image of the field at which the gun sight is directed; a first reticule member movable in a direction substantially parallel to said plane; a second reticule member movable in a direction crossing the line of movement of said first reticule member and substantially parallel to said plane, both said reticules being located within the field of view of said sight; a gun support having universal movement relative to said gun sight so as to be aimed at a point in said field; means connecting said gun to said first reticule member so that a movement of said gun in a first plane will move said first reticule memher; and means connecting said gun to said sec- 0nd reticule member so that movement of said gun in a second plane at a substantial angle'to said first plane will move said second reticule member, whereby the positions or said reticule members will indicate imsaid image the point in said field at which the gun is aimed.

tion crossing said first direction; agun supported for universal movement relative to said gun sight and so as to be aimed at points in said field; means operating to move said first frame in said first plane when said gun is moved relative to said gun sight in one direction; and means operating to move said second frame in said second direction when said gun is moved relative to said gun sight in a second plane disposed at a substantial angle to said first named plane.

11. In a gunnery device of the character described, the combination of: a gun sight having means defining a plane intercepting the path of light carrying an image from a field to a receiving optical element; a gun mounted for movement relative to said gun sight and so as to be aimed at points in said field; means connected to said gun so as to be controlled in accordance with the movement of said gun, to indicate in said plane a point positioned in accordance with the point in said field at which said gun is aimed; and adjusting means associated with said last named means to vary the functioning of said last named means in a manner to embrace corrections for conditions encountered in the practical use of the device. i

12, In a gunnery device of the character described, the combination of: a telescopic gun sight having optical means to produce an image of the field at which the gun sight is directed; a reticule movable in the field of view of said gun sight; a gun mounted for movement relative to said gun sight and so as to-be aimed at points in said field; and means connected to said gun and to said reticule and operating to move said reticule in accordance with the movement of said gun and in such proportion to the movement of said gun as to introduce in the movement of said reticule corrections to compensate for conditions which may be encountered in the practical use of the device. 4

13. In a gunnery device of the character described, the combination of: a gun sight having optical means to produce an image of a field toward which the gun sight is directed; a gun mounted for movement relative to said gun sight whereby it may be aimed at different points in said field; movable reticule means for producing a reticule image in the field of view of said gun sight; and means connected to said gun and to said reticule means operating in response to movement of said gun relative to said gun sight to move said reticule means in accordance with saio movement of said gun.

14. In a. gunnery device of the character described, the combination of a gun sight having optical means for bringing to the vision of a gunnet the field toward which the gun sight is directed; a gun mounted for movement relative to said gun sight whereby said gun may have aiming movement in' said field; movable reticule means in said field for reference of the gunner in aiming said gun; and control means connected to said gun and to said reticule means to move said reticule means in said field in accordance with said movement of said gun relative to the gun sight, said control means being so formed as to produce movements of said reticule means in said field of such proportions of the corresponding movements of said gun in said field as to compensate for tangent and distortion errors in said gun sight.

15. In a gunnery device of the character described, for use in aircraft, the combination of:

a gun sight having optical means for bringing to the vision of a gunner the field toward which the gun sight is directed; a gun mounted for movement relative to said gun sight whereby aid gun may have aiming movement in said field; movable reticule means in said field for reference of the gunner in aiming said gun; and control means connected to said gun and to said reticule means to move said reticule means in said field in accordance with said movement of said gun relative to the gun sight, said control means being so formed as to produce movements of said reticule means in said field of such proportions of the corresponding movements of said 5 to move said frames along their respective lines gun in said field as to compensate for kinematic errors in the use of the gun sight with the gun.

In a nnery device ofthe character described, for use in aircraft, the combination of z a gun sight having optical means for bringing to the vision of a gunner the field toward which the gun sight is directed; a gun mounted for movement relative to said gun sight whereby said gun may have aiming movement in said field; movable reticule means in said field for reference of the gunner in aiming said gun; and control means connected to said gun and to said reticule means to move said reticule means in said field in accordance with said movement of said gun relative to the gun sight, said control means being so formed as to produce movements of said reticule means in said field of such proportions of the corresponding movements of said gun in said field as to compensate for phoronomic errors in the use of the gun sight with the gun.

17. In a gunnery device of the character described, for use in aircraft, the combination of: a gun sight having optical means for bringing to the vision of a gunner the field toward which the gun sight is directed; a gun mounted for movement relative to said gun sight whereby said gun may have aiming movement in'said field; movable reticule means in said field for reference of the gunner inaiming said gun; and control means connected to said gunand to said reticule means to move said reticule means in said field in accordance with said movement of said gun relative to the gun sight, said control means being so formed as to produce movements of said reticule means in said field of such proportions of the corresponding movements of said gun in said field as to compensate for errors in the gun sight proper and for kinematic errors,

with an increase in the excursion of the reticule means relative to the excursion of the gun to compensate for phoronomic error.

18. In reticule means for use with a gun sight, the combination of a reticule housing; movable reticule means in said housing; a first reticule frame movable along a first line of movement; a second reticule frame movable in a second line of movement which crosses said first line of movement at a substantial angle, said frames having sliding engagement with said reticule means; and means operative from the exterior of movement, whereby the cooperative movement of said frames will move said reticule means in a plurality of directions. I

19. In reticule means for use with a gun sight, the combination of: a reticule housing; movable reticule means in said housing; a first reticule frame movable along a first line of movement; a second reticule frame movable in a second line of movement which crosses said first line of movement at a substantial angle, said frames having sliding engagement with said reticule means; screw means connected to said frames to move the same; spools connected to said screw means to rotate the same; and cable means running on said spool means to impart rotation thereto.

20. In a gunnery device of the character described, the combination of: a telescopic gun sight having means to produce in a plane an image of the field at which the gun sight is directed; a first reticule member movable in a direction substantially parallel to said plane; a second reticule member movable in a direction crossing the line of movement of said first reti- WOLFGANG B. KLEMPERER. 

